clang-error: fix clang-analyzer-deadcode.DeadStores error

This clang error is generated when the value stored to a variable
is never read in the code.

Change-Id: Ib68741b3aaf8856010d0073675abc2fdb3012712
Signed-off-by: Pavithra Barithaya <pavithra.b@ibm.com>
diff --git a/oem/ibm/test/libpldmresponder_fileio_test.cpp b/oem/ibm/test/libpldmresponder_fileio_test.cpp
index 18b7970..d9d68e7 100644
--- a/oem/ibm/test/libpldmresponder_fileio_test.cpp
+++ b/oem/ibm/test/libpldmresponder_fileio_test.cpp
@@ -980,6 +980,7 @@
     auto fd = mkstemp(tmplt);
     std::vector<uint8_t> in = {100, 10, 56, 78, 34, 56, 79, 235, 111};
     rc = write(fd, in.data(), in.size());
+    ASSERT_NE(rc, PLDM_ERROR);
     close(fd);
     length = in.size() + 1000;
     rc = handler.readFile(tmplt, 0, length, response);